U.S. patent number 10,930,820 [Application Number 16/428,959] was granted by the patent office on 2021-02-23 for light emitting device.
This patent grant is currently assigned to NICHIA CORPORATION. The grantee listed for this patent is NICHIA CORPORATION. Invention is credited to Kiyoshi Enomoto, Kazuma Kozuru.
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United States Patent |
10,930,820 |
Kozuru , et al. |
February 23, 2021 |
Light emitting device
Abstract
A light emitting device includes a semiconductor laser element
and a base member. The base member includes a bottom part, a frame
part, and first and second electrode layers. The frame part forms a
frame surrounding the semiconductor laser element. An area within
an intersection line between the first inner surface and the
bonding surface of the frame part has a size larger than a size of
the arrangement surface of the bottom part. An area within an
intersection line between the second inner surface and the bonding
surface of the frame part has a size smaller than the size of the
arrangement surface. The planar surface of the frame part
intersects at least a part of the second inner surface. The planar
surface and the second inner surface form a step portion on an
inner side of the frame. The second electrode layer is disposed on
the planar surface.
Inventors: |
Kozuru; Kazuma (Tokushima,
JP), Enomoto; Kiyoshi (Tokushima, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
NICHIA CORPORATION |
Anan |
N/A |
JP |
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|
Assignee: |
NICHIA CORPORATION (Anan,
JP)
|
Family
ID: |
1000005379534 |
Appl.
No.: |
16/428,959 |
Filed: |
May 31, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20190371971 A1 |
Dec 5, 2019 |
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Foreign Application Priority Data
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Jun 5, 2018 [JP] |
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JP2018-107569 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
24/48 (20130101); H01L 33/62 (20130101); H01L
33/486 (20130101); H01L 33/38 (20130101); H01L
33/641 (20130101); H01L 24/08 (20130101); H01L
33/642 (20130101); H01L 33/54 (20130101); H01L
2224/48091 (20130101); H01L 2924/15174 (20130101); H01L
2224/48227 (20130101) |
Current International
Class: |
H01L
33/48 (20100101); H01L 23/00 (20060101); H01L
33/38 (20100101); H01L 33/62 (20100101); H01L
33/54 (20100101); H01L 33/64 (20100101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2006-216764 |
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Aug 2006 |
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JP |
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2007-214524 |
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Aug 2007 |
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JP |
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2007-234846 |
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Sep 2007 |
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JP |
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2008-172113 |
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Jul 2008 |
|
JP |
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2014-068013 |
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Apr 2014 |
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JP |
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2018-0053284 |
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May 2018 |
|
KR |
|
Primary Examiner: Nguyen; Cuong B
Attorney, Agent or Firm: Global IP Counselors, LLP
Claims
What is claimed is:
1. A light emitting device comprising: at least one semiconductor
laser element; and a base member including: a bottom part
containing a metal as a main material of the bottom part, and
having an arrangement surface on which the at least one
semiconductor laser element is arranged, a frame part containing a
ceramic as a main material of the frame part, bonded to the bottom
part, and forming a frame surrounding the at least one
semiconductor laser element, the frame part having a bonding
surface bonded to a portion of the arrangement surface, a first
inner surface intersecting the bonding surface around a periphery
of the bottom part in a plan view, an area within an intersection
line between the first inner surface and the bonding surface in the
plan view having a size larger than a size of the arrangement
surface, a second inner surface intersecting the bonding surface
over the arrangement surface, an area within an intersection line
between the second inner surface and the bonding surface in the
plan view having a size smaller than the size of the arrangement
surface, and a planar surface intersecting at least a part of the
second inner surface, and being different from the bonding surface,
the planar surface and the second inner surface forming a step
portion on an inner side of the frame, and first and second
electrode layers each electrically connected to the at least one
semiconductor laser element, the second electrode layer being
disposed on the planar surface of the frame part.
2. The light emitting device according to claim 1, wherein the
second inner surface has a region intersecting the bonding surface
and the planar surface, and a region intersecting the bonding
surface, and not intersecting the planar surface.
3. The light emitting device according to claim 1, wherein the base
member has a bottom surface on a side opposite to the arrangement
surface, each of the bottom part and the frame part has a bottom
surface such that the bottom surface of the bottom part and the
bottom surface of the frame part correspond to the bottom surface
of the base member, and a gap is present between the bottom surface
of the bottom part and the bottom surface of the frame part.
4. The light emitting device according to claim 3, wherein a gap is
present between a lateral surface of the bottom part and the first
inner surface of the frame part over a region ranging from the
bonding surface to the bottom surface of the base member.
5. The light emitting device according to claim 3, wherein the
frame part has a quadrangular shape in the plan view, and the
bottom surface of the frame part has two opposite sides having the
same width, and two adjacent sides having different widths.
6. The light emitting device according to claim 3, wherein the
first electrode layer is disposed on the bottom surface of the
frame part, the bottom surface of the frame part has a polygonal
shape in the plan view, and the bottom surface of the frame part
has a side provided with the first electrode layer and a side not
provided with the first electrode layer, such that the side
provided with the first electrode layer has a width larger than a
width of the side not provided with the first electrode layer.
7. The light emitting device according to claim 3, wherein the gap
between the lateral surface of the bottom part and the first inner
surface is larger along a plane corresponding to the bottom surface
than along a plane corresponding to the bonding surface.
8. The light emitting device according to claim 7, wherein the
bottom surface of the bottom part has a size smaller than a size of
the arrangement surface.
9. The light emitting device according to claim 8, wherein the
bottom part has a depressed portion at an outer edge of the bottom
surface of the bottom part.
10. The light emitting device according to claim 8, wherein the
bottom part further has a lateral surface inclined from the
arrangement surface to the bottom surface of the bottom part.
11. The light emitting device according to claim 7, wherein in the
frame part, the size of the area within the intersection line
between the first inner surface and the bonding surface is smaller
than a size of an area within an intersection line between the
first inner surface and the bottom surface of the frame part in the
plan view.
12. The light emitting device according to claim 3, wherein the
bottom surface of the bottom part has a circular shape.
13. The light emitting device according to claim 3, further
comprising a substrate including an insulating portion, and a heat
dissipation portion including a protruding section having an
exposed surface exposed from the insulating portion, the protruding
section having a protruded shape in a cross-sectional view, the
exposed surface having a shape corresponding to a shape of the
bottom surface of the bottom part in the plan view, and the exposed
surface being bonded to the bottom surface of the bottom part.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to Japanese Patent Application No.
2018-107569, filed on Jun. 5, 2018. The entire disclosure of
Japanese Patent Application No. 2018-107569 is hereby incorporated
herein by reference.
BACKGROUND
1. Technical Field
The present disclosure relates to a light emitting device.
2. Description of Related Art
A light emitting element package including a base part, which
includes a frame and an upward-facing surface, and a light emitting
element such as a LED element or a semiconductor laser element on
the upward-facing surface of the base part has been known. In
addition, various materials can be employed for a base member
serving as a package body, and examples of the materials include
ceramics. JP 2014-68013 A describes a light emitting element
package in which a light emitting element is disposed on a surface
of a package body formed by a ceramic layer.
SUMMARY
On the other hand, because a light emitting element such as a
semiconductor laser element generates heat, heat dissipation is
required to be considered when manufacturing a light emitting
element package. The light emitting element package described in JP
2014-68013 A has a structure in which a light emitting element is
disposed on a ceramic, and has room for improvement with regards to
heat dissipation.
A light emitting device according to certain embodiments includes
at least one semiconductor laser element and a base member. The
base member includes a bottom part, a frame part, and first and
second electrode layers. The bottom part contains a metal as a main
material, and has an arrangement surface on which the semiconductor
laser element is arranged. The frame part contains a ceramic as a
main material, is bonded to the bottom part, and forms a frame
surrounding the semiconductor laser element. The frame part has a
bonding surface, a first inner surface, a second inner surface and
a planar surface. The bonding surface is bonded to a portion of the
arrangement surface. The first inner surface intersects the bonding
surface around a periphery of the bottom part in a plan view. An
area within an intersection line between the first inner surface
and the bonding surface in the plan view has a size larger than a
size of the arrangement surface. The second inner surface
intersects the bonding surface over the arrangement surface. An
area within an intersection line between the second inner surface
and the bonding surface in the plan view has a size smaller than
the size of the arrangement surface. The planar surface intersects
at least a part of the second inner surface, and is different from
the bonding surface. The planar surface and the second inner
surface form a step portion on an inner side of the frame. The
first and second electrode layers is each electrically connected to
the semiconductor laser element. The second electrode layer is
disposed on the planar surface of the frame part.
According to certain embodiments of the present disclosure, a light
emitting device having good heat dissipation performance can be
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of a light emitting device
according to a first embodiment.
FIG. 2 is a schematic top view for illustrating an internal
structure of the light emitting device according to the first
embodiment.
FIG. 3 is a schematic cross-sectional view of the light emitting
device taken along a line in FIG. 1.
FIG. 4A is a schematic perspective view for illustrating a method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 4B is a schematic cross-sectional view taken along a line
BI-BI in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 4C is a sectional view taken along a line BII-BII in FIG. 4A
for illustrating the method of manufacturing the light emitting
device according to the first embodiment.
FIG. 4D is a schematic perspective view of a bottom part of the
light emitting device according to the first embodiment.
FIG. 4E is a schematic top view of a frame part of the light
emitting device according to the first embodiment.
FIG. 4F is a schematic bottom view of the frame part of the light
emitting device according to the first embodiment.
FIG. 5A is a schematic perspective view for illustrating the method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 5B is a schematic cross-sectional view taken along a line
BI-BI in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 5C is a schematic cross-sectional view taken along a line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 6A is a schematic perspective view for illustrating the method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 6B is a schematic cross-sectional view taken along line BI-BI
in FIG. 4A for illustrating the method of manufacturing the light
emitting device according to the first embodiment.
FIG. 6C is a schematic cross-sectional view taken along line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 7A is a schematic perspective view for illustrating the method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 7B is a schematic cross-sectional view taken along line BI-BI
in FIG. 4A for illustrating the method of manufacturing the light
emitting device according to the first embodiment.
FIG. 7C is a schematic cross-sectional view taken along line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 8A is a schematic perspective view for illustrating the method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 8B is a sectional view on line BI-BI in FIG. 4A for
illustrating the method of manufacturing the light emitting device
according to the first embodiment.
FIG. 8C is a schematic cross-sectional view taken along line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 9A is a schematic perspective view for illustrating the method
of manufacturing the light emitting device according to the first
embodiment.
FIG. 9B is a schematic cross-sectional view taken along line BI-BI
in FIG. 4A for illustrating the method of manufacturing the light
emitting device according to the first embodiment.
FIG. 9C is a schematic cross-sectional view taken along line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 9D is a schematic top view of a substrate of the light
emitting device according to the first embodiment.
FIG. 10A is a schematic view for illustrating the method of
manufacturing the light emitting device according to the first
embodiment.
FIG. 10B is a schematic cross-sectional view taken along line BI-BI
in FIG. 4A for illustrating the method of manufacturing the light
emitting device according to the first embodiment.
FIG. 10C is a schematic cross-sectional view taken along line
BII-BII in FIG. 4A for illustrating the method of manufacturing the
light emitting device according to the first embodiment.
FIG. 11 is a schematic cross-sectional view of a light emitting
device according to a second embodiment.
FIG. 12A is a schematic perspective view of a bottom part of the
light emitting device according to the second embodiment.
FIG. 12B is a schematic perspective view of the bottom part of the
light emitting device according to the second embodiment.
FIG. 13 is a schematic top view of a substrate of the light
emitting device according to the second embodiment.
FIG. 14 is a schematic cross-sectional view of a light emitting
device according to a first modified example.
FIG. 15 is a schematic cross-sectional view of a light emitting
device according to a second modified example.
FIG. 16 is a schematic cross-schematic perspective view of a bottom
part of the light emitting device according to the second modified
example.
DETAILED DESCRIPTION OF EMBODIMENTS
Certain embodiments of the present invention will be described
below with reference to the drawings. The embodiments shown below
are intended to embody the technical idea of the present invention,
and are not intended to limit the scope of the present invention.
Further, in the descriptions below, the same names and reference
numerals denote the same or similar members, and detailed
descriptions thereof are omitted as appropriate. The sizes,
positional relationships and the like of members shown in the
drawings may be exaggerated for clarity of description.
First Embodiment
FIG. 1 is a schematic view of a light emitting device 1 according
to a first embodiment, FIG. 2 is a top view for illustrating an
internal structure of a base member of the light emitting device,
and FIG. 3 is a sectional view taken along on line in FIG. 1. In
FIG. 2, for showing the internal structure, a cover 120, an
adhesion portion 130 and a lens member 140 are indicated by a
broken line, and portions which are seen when viewed through the
cover 120, the adhesion portion 130 and the lens member 140 are
indicated with a solid line. In addition, for avoiding complication
of the drawings, a wire 180 as shown in FIG. 3 is omitted in FIG.
2.
In the light emitting device 1, light radiated from a plurality of
semiconductor laser elements 170 is reflected by a light reflecting
surface of light reflecting members 150, and is emitted outside
through the lens member 140. As shown in FIG. 2, three sub-mounts
160, on each of which at least one of the semiconductor laser
elements 170 is disposed, are arranged, and the light reflecting
members 150 are disposed each corresponding to at least one of the
semiconductor laser elements 170. Each of the plurality of
semiconductor laser elements 170 radiate light to a corresponding
one of light reflecting members 150, and the corresponding light
reflecting member 150 reflects light from the corresponding
semiconductor laser element 170 toward the lens member 140. The
light emitting device 1 includes a package configured to emit
light, and a mounting substrate on which the package is mounted.
Alternatively, a light emitting device without the mounting
substrate may be considered as the light emitting device 1.
The light emitting device 1 includes a substrate 100 as the
mounting substrate, and also includes a base member 110, the cover
120, the adhesion portion 130, the lens member 140, the light
reflecting members 150, the sub-mounts 160, the semiconductor laser
elements 170, and the wires 180, which are constituent elements
included in the package. In addition, in a sealed space formed by
bonding the base member 110 to the cover 120, the light reflecting
members 150 and the sub-mounts 160 on each of which at least one of
the semiconductor laser elements 170 is disposed are arranged.
Further, the wires 180 for electrically connecting semiconductor
laser elements 170 disposed on the base member 110 are provided. In
addition, as shown in FIG. 3, the base member 110 includes a frame
part 111 and a bottom part 118.
The substrate 100 is bonded to the frame part 111 and/or the bottom
part 118. In addition, the frame part 111 is bonded to the cover
120 at a side opposite to a bonding surface bonded with the
substrate 100. The cover 120 is bonded to the lens member 140 with
an adhesive agent disposed therebetween. The adhesion portion 130
is formed by solidification of the adhesive agent. A gap is created
between the cover 120 and the lens member 140 by forming the
adhesion portion 130. Hereinafter, the light emitting device 1 will
be described along with description of operations in manufacturing
of the light emitting device 1.
FIGS. 4A to 10A are schematic views for illustrating operations
until the light emitting device 1 is obtained. In addition, FIGS.
4B to 10B or 4C to 10C show schematic cross-sectional views in the
steps so as to correspond to FIGS. 4A to 10A, respectively. FIGS.
4B to 10B are schematic cross-sectional views corresponding to line
BI-BI shown in FIG. 4A. FIGS. 4C to 10C are schematic
cross-sectional views corresponding to line BII to BII shown in
FIG. 4A. Dotted lines S1 and S2 are not constituent elements of a
light emitting element 2, but auxiliary lines for indicating
correspondence in directions of the light emitting device 2 in the
respective drawings. In addition, an auxiliary line in each
cross-sectional view indicates a front side of the cross-sectional
view, such that the auxiliary line in each cross-sectional view
corresponds to a corresponding one of the auxiliary lines in the
schematic view in a corresponding one of FIGS. 4A, 5A, 6A, 7A, 8A,
9A, and 10A. For example, the cross-sectional view of the base
member 110 in FIG. 5B with a line S1 is taken along a line
corresponding to a line BI-BI in FIG. 4A, where the front face in
FIG. 5B is at the S1 line side of the base member 110 in FIG.
5A.
As shown in FIGS. 4A and 4D, the frame part 111 and the bottom part
118 which form the base member 110 are provided. A metal such as Cu
or Al can be used for the bottom part 118, and a ceramic such as
alumina (Al.sub.2O.sub.3) or AlN can be used for the frame part
111. Any appropriate material may be used for the bottom part 118,
but at least, the bottom part 118 has a heat dissipation higher
than that of the frame part 111, and the bottom part 118 has a
thermal conductivity higher than that of the frame part 111.
The bottom part 118 includes a bonding surface bonded to the
substrate 100, and an arrangement surface on which the light
reflecting member 150, the sub-mount 160 and the semiconductor
laser element 170 are disposed. Each of the bonding surface and the
arrangement surface has a rectangular shape. In addition, the
thickness from the bonding surface to the arrangement surface is
substantially uniform. In the present disclosure, a rectangular
shape with modified corners such as rounded corners and/or slanted
corners is also referred to as "a rectangular shape". Similarly, a
polygonal shape with rounded corners or the like is also referred
to as a "polygonal shape". In addition, when a corner of a
rectangular shape or a polygonal shape is modified, the modified
corner portion is considered to be included in a corresponding side
of the rectangular shape or the polygonal shape. A surface bonded
to the substrate 100 is considered as a bottom surface. The bonding
surface of the bottom part 118 can be regarded as the bottom
surface. The bottom surface and the arrangement surface may
alternatively have any appropriate shapes other than the shapes
described above.
The frame part 111 has a first electrode layer 112 at the bottom
surface, which is a surface bonded to the substrate 100. The first
electrode layer 112 includes, for example, a metal layer, and is
bonded to a metal film 103 of the substrate 100. Electric power is
supplied to the semiconductor laser element 170 through the metal
film 103. In addition, the frame part 111 has a step portion inside
the frame. The step portion included in the frame part 111 extends
inward of the frame part 111, and a planar surface of the step
portion at the bottom surface 118 side is a bonding surface 113
bonded to the bottom part 118. Thus, the planar surface
intersecting the inner surface 116 form a step portion with the
inner surface 116 on an inner side of the frame formed by the frame
part 111. In the present specification, of two opposite planar
surfaces, a planar surface closer to the substrate 100 is referred
to as a "lower surface", and a planar surface opposite to the lower
surface is referred to as an "upper surface", for the sake of
convenience. Alternatively, a planar surface closer to the lens
member 140 is referred to as an "upper surface", and the surface
opposite to the upper surface is referred to as a "lower surface".
In FIG. 4A, the frame part 111 is arranged such that the upper
surface faces downward and the lower surface faces upward.
FIG. 4E is a top view of the frame part 111, and FIG. 4F is a
bottom view of the frame part 111. The frame part 111 includes the
bonding surface 113 at a planar surface of the step portion 111
that is seen in a bottom view (that is, the lower surface of the
step portion 111). A second electrode layer 114 to be electrically
connected to a semiconductor laser element 170 is disposed at the
planar surface of the step portion that is seen in a top view (that
is, the lower surface of the step portion 111). The planar surface
intersects at least a part of the inner surface 117, and is
different from the bonding surface 113. The second electrode layer
114 is electrically connected to the first electrode layer 112
through, for example, a via hole. The second electrode layer 114
includes, for example, a metal layer, and is arranged on a ceramic
layer, and therefore is not exposed to the lower surface of the
step portion. Further, in the bottom view, the step portion is
disposed along all of the four sides of the frame part 111, but in
the top view, the step portion is disposed along only three sides
of the four sides of the frame part 111, and is not disposed along
the other one side of the four sides except for end portions
overlapping two sides at both ends. That is, the region having the
step portion in the top view does not correspond to the region
having the step portion in the bottom view. For bonding of the
bonding surface 113 of the step portion to the bottom part 118, the
step portion is disposed along the entire periphery of the frame
part 111 in the bottom view. On the other hand, the planar surface
of the step portion that is seen in the top view has a region
sufficient for disposing the second electrode layer, and is not
necessarily disposed along the entire periphery.
In addition, the bonding surface 113 has a width along a side
opposite to a side not provided with the second electrode layer 114
larger than a width of the bonding surface 113 along each of other
sides of the bonding surface 113. On the other hand, a surface of
the frame part 111 bonded to the substrate 100 is designed such
that a width along a side not provided with the second electrode
layer 114 and a width along a side opposite thereto is the same. In
other words, the shortest distance between a pair of opposite
lateral surfaces of the frame part 111 meeting the surface of the
frame part 111 bonded with the substrate 100 and the shortest
distance between another pair of opposite lateral surfaces of the
frame part 111 intersecting the surface of the frame part 111
bonded with the substrate 100 are the same at corresponding
positions of each pair of opposite sides. The term "the same" as
used herein refers to that a difference between two or more values
to be compared is within a design tolerance. With such a structure,
a force applied to the base member 110 at the time of bonding the
frame to the substrate 100 by soldering can be balanced. The term
"corresponding positions of each pair of opposite sides" as used
herein refers to, with two sides opposite to and parallel to each
other, a certain position in one of the two sides and a position in
the other of the two sides with the shortest distance
therebetween.
Next, as shown in FIG. 5A, the bonding surface 113 of the frame
part 111 is bonded to the bottom part 118. For the bonding, for
example, a silver brazing material containing Ag as a main
component and containing Cu can be used, and other metal brazing
materials can also be used. As shown in FIG. 4A, silver brazing
material is applied to the bonding surface of the frame part 111
while the bottom surface of the frame part 111 faces upward, and
the bottom part 118 is placed inside the frame of the frame part
111 with the silver brazing material melted by heating. The silver
brazing material is then cooled to bond the frame part 111 to the
bottom part 118, so that the base member 110 is formed. The silver
brazing material is applied to a bonding region between the frame
part 111 and the bottom part 118, with the bonding region plated
with Ni.
Thus, as shown in FIGS. 5B and 5C, the bonding surface of the
bottom part 118 bonded to the frame part 111 has a size smaller
than a size of a frame formed by an inner surface 115 (first inner
surface) intersecting the bottom surface of the frame part 111, and
is located inward of the frame formed by the inner surface 115. In
other words, the inner surface 115 intersects the bonding surface
113 around a periphery of the bottom part 118 in a plan view, and
an area within an intersection line between the inner surface 115
and the bonding surface 113 in the plan view having a size larger
than a size of the arrangement surface of the bottom part 118.
Further, the shapes of the inner surface 115 of the frame part 111
and a lateral surface 119 of the bottom part 118 are designed so
that the arrangement surface of the bottom part 118 is bonded to
the bonding surface 113 at the step portion of the frame part 111.
The light emitting device 1 according to the first embodiment is
designed so that the height from the bottom surface of the frame
part 111 to the bonding surface 113 is the same as the height of
the bottom part 118, and the periphery of the bottom part 118 is
located inward of the frame formed by the inner surface 115
intersecting the bonding surface 113.
Further, a gap is generated between the inner surface 115 and the
lateral surface 119. As described above, the frame part 111 can be
formed of a ceramic, and the degree of sintering in manufacturing
may not be constant. Thus, shapes and/or size of manufactured frame
parts 111 may be varied. In manufacturing of the light emitting
device 1, with consideration of design tolerance, the shapes of the
frame part 111 and the bottom part 118 are designed so as to
generate a gap of 0.1 mm between the frame part 111 and the bottom
part 118. The shapes of the frame part 111 and the bottom part 118
may be designed such that a gap of 0.1 mm or more or a gap of 0.1
mm or less is present.
The size of the gap is preferably in a range of 0.1 mm to 0.5 mm.
Accordingly, the bottom part 118 can be properly bonded to the
bonding surface of the frame part 111, and the heat dissipation
property of the bottom part 118 can be improved, so that the base
member 110 excellent in heat dissipation property can be
formed.
The size of the planar surface of the bottom part 118, which is
bonded to the bonding surface 113, is larger than the size of a
frame formed by the step portion. More specifically, the size of
the planar surface of the bottom part 118, which is bonded to the
bonding surface 113 of the frame part 111, is larger than the size
of the frame formed by an inner surface 116 (second inner surface)
intersecting an inner end of the bonding surface 113, and the frame
formed by the inner surface 116 is covered with the bottom part
118. In other words, the inner surface 116 intersects the bonding
surface 113 over the arrangement surface, and an area within an
intersection line between the inner surface 116 and the bonding
surface 113 in the plan view having a size smaller than the size of
the arrangement surface.
In addition, the relationship between the frame formed by the inner
surface 115 intersecting an inner end of the bottom surface of the
frame part 111 and the frame formed by an inner surface 117 (second
inner surface) intersecting an inner end of the upper surface of
the frame part 111 is such that the width of the frame formed by
the inner surface 115 is larger than the width of the frame formed
by the inner surface 117 when seen in the S1 direction, and the
widths of both frames are the same as each other when seen in the
S2 direction. In the S1 direction, there is a side along which the
step portion for the second electrode layer is not formed in top
view, and the width of the frame at the lower surface side is
larger than the width of the frame at the upper surface side for
forming the bonding surface at the side corresponding to the side
along which the step portion is not formed.
In the S2 direction, both sides are provided with the step portion
for the second electrode layer, and therefore the bonding surface
can be formed using a region corresponding to the step portion, so
that the width of the frame at the lower surface side may not be
larger than the width of the frame at the upper surface side.
Both sides of the frame part 111 when viewed in the S2 direction
are provided with the first electrode layer on the bottom surface
of the frame part 111. Both sides of the frame part 111 when viewed
in the S1 direction are not provided with the first electrode layer
on the bottom surface of the frame part 111.
In view of a heat dissipation performance, it is preferable that
the bottom part 118 have a large size. Meanwhile, when the width of
the bottom surface of the frame part 111 is reduced, at the time of
performing soldering, solder may be brought into contact with or
connected to both the first electrode layer and the bottom part
118. While the inner surfaces 115 and 117 are not required to have
the same size as each other when viewed in the S2 direction, the
inner surface 115 is located at a predetermined distance from the
first electrode layer. The position of the inner end of the bottom
surface of the frame part 111 is determined with a spacing of 0.3
mm or more from the first electrode layer having a width of 0.5 mm.
The first electrode layer 112 is electrically connected to the
second electrode layer 114 through a conductive portion provided
inside the frame part 111.
An additional explanation will be given about determination of the
structures of the frame part 111 and the bottom part 118. In view
of a heat dissipation performance, a material having a good heat
dissipation is desired to be used for the bottom part 118 so that
heat is diffused from a position at which the semiconductor laser
element 170, which is a main heat source, is arranged, so that a
metal such as Cu is more preferably used for the bottom part 118
than a ceramic. In addition, the bottom part 118 is preferably
large at a certain degree, and it is preferable that a portion
exposed as an arrangement surface is made of metal. Further, for
bonding the bottom surface 118 to the substrate 100, and
effectively dissipating heat to the substrate 100 through the
bonded portion, it is preferable that a material having poor heat
dissipation is not disposed between the arrangement surface and the
bonding surface bonded with the substrate 100.
In addition, in view of strength, and shape stability at the time
of using the light emitting device 1, it is preferable that the
outer frame of the base member is made of ceramic. Further, in
order to provide a metal layer for electrically connecting the
semiconductor laser element, it is necessary to form a step portion
at a part of the ceramic frame. Accordingly, the base member 110 in
the light emitting device 1 is required to include at least: a
frame that surrounds the periphery; a bottom part on which a
semiconductor laser is disposed; and a step portion for providing a
metal layer.
The step portion in a top view is not required to be provided over
the entire inner periphery of the frame part 111, and a region to
be provided with the step can be appropriately adjusted according
to the number of semiconductor laser elements 170 arranged in the
light emitting device 1, or a combination in arrangement of a
plurality of semiconductor laser elements 170. For example, the
step portion is provided along one side or two sides of the frame
part 111, or it may be necessary to provide the step portion over
the entire periphery. The "combination in arrangement of a
plurality of semiconductor laser elements 170" refers to, for
example, a case where semiconductor laser elements having the same
color and the same performance are disposed, or a case where
semiconductor laser elements having different colors are
disposed.
With consideration of these, a metal is used for the bottom part
118 while the frame part 111 is formed of a ceramic, so that
interface between the frame part and the bottom part is formed for
improving the heat dissipation. Further, a gap is provided with
consideration of a design tolerance associated with a ceramic.
Thus, it is possible to provide the base member 110 having good
heat dissipation compared to a case where the arrangement surface
of the base member 110 on which the semiconductor laser element 170
is disposed is formed of a ceramic.
In FIG. 6A, the light reflecting member 150, and the sub-mount 160
on which the semiconductor laser element 170 is arranged are bonded
to the arrangement surface of the formed base member 110. The
position at which the light reflecting member 150 and the sub-mount
160 are disposed is determined according to a position based on the
frame part 111 rather than a position based on the bottom part 118.
That is, the light reflecting member 150 and the sub-mount 160 are
disposed according to, rather than a distance or a coordinate from
a specific position on the bottom part 118, a distance or a
coordinate from a predetermined position on the frame part 111.
A gap is generated between the frame part 111 and the bottom part
118 as described above, so that the bottom part 118 is movable in a
frame formed by the frame part 111 before the bottom part 118 is
fixed with the frame part 111. Therefore, the bottom part 118 may
move at the time of performing bonding by brazing. For example, in
the light emitting device 1, the shape of the frame of the frame
part 111 is similar to the shape of the bonding surface of the
bottom part 118, but as a result of performing bonding, the center
points of the frame part 111 and the bottom part 118 may not
correspond to each other, or the distance between the frame part
111 and the bottom part 118 may not be uniform. Therefore, it is
preferable to adjust the arrangement position so that the position
with respect to the frame part 111 is uniform for easily performing
alignment between manufactured light emitting devices 1 even when
the bottom part 118 is misaligned. The smaller the gap between the
frame part 111 and the bottom part 118, the smaller the
misalignment due to shifting.
The light reflecting member 150 has a light reflecting surface at
one or more surfaces. The light reflecting member 150 is irradiated
with light radiated from the semiconductor laser element 170, and
therefore in the light reflecting member 150, it is desirable that
a material resistant to heat be used as a main material, and a
material having a high reflectivity be used for the light
reflecting surface. Glass such as quartz or BK7 (borosilicate
glass), a metal such as aluminum, S1 or the like can be employed as
a main material of the light reflecting member 150, and a metal, a
dielectric multilayer film or the like can be employed for the
light reflecting surface. If necessary, in the light emitting
device 1, the light reflecting member 150 may have a plurality of
light emitting surfaces, or a light reflecting member may be
disposed in addition to the light reflecting member 150. Further, a
respective one of light reflecting members 150 is provided for a
respective one of semiconductor laser elements 170, but one light
reflecting member 150 may be arranged for three semiconductor laser
elements 170, or one light reflecting member 150 may be provided
for a plurality of semiconductor laser elements.
For the sub-mount 160, aluminum nitride, or silicon carbide can be
used. The sub-mount 160 is provided with a metal film, and the
semiconductor laser element 170 is fixed to the sub-mount 160 via
an electrically conductive layer of Au--Sn or the like.
The semiconductor laser element 170 is bonded to the sub-mount 160
at the bottom surface thereof, and radiates light from a lateral
surface closer to the light reflecting member 150. Laser light
radiated from the semiconductor laser element 170 has an elliptical
far-field pattern (hereinafter, referred to as "FFP") having a
length in a layering direction of a plurality of semiconductor
layers including an active layer is larger than a length thereof in
a direction perpendicular to the layering direction, on a surface
parallel to a light emitting end surface.
The "FFP" as used herein refers to a light intensity distribution
of radiated light measured on a surface apart from the light
emitting end surface of the semiconductor laser element to a
certain degree and parallel to the light emitting end surface. The
shape of the FFP is specified as a shape given by a main part of
light. Here, the main part of light from the laser element refers
to a part of laser light with an intensity range of a peak
intensity value to any appropriate lower intensity value such as
1/e.sup.2.
The light emitting device 1 includes one or more semiconductor
laser elements 170, and in FIGS. 6A to 6C, three semiconductor
laser elements 170 are disposed. The number of the disposed
semiconductor laser elements 170 is not limited to 3, and may be 1
or more. Light emitted from these semiconductor laser elements 170
may have the same color, or different colors. For example, the
three semiconductor laser elements 170 of the light emitting device
1 may include a first semiconductor laser element which emits red
light; a second semiconductor laser element which emits green
light; a third semiconductor laser element which emits blue
light.
The peak emission wavelength of red light is in a range of, for
example, 605 nm to 750 nm. Examples of the semiconductor laser
element which emits red light include those containing a
semiconductor of InAlGaP type, GaInP type, GaAs type or AlGaAs
type. The peak emission wavelength of green light is in a range of,
for example, 495 nm to 570 nm. Examples of the semiconductor laser
element which emits green light include semiconductor laser
elements containing a nitride semiconductor. The peak emission
wavelength of blue light is in a range of, for example, 420 nm to
494 nm. Examples of the semiconductor laser element which emits
blue light include semiconductor laser elements containing a
nitride semiconductor. Examples of the nitride semiconductor
include GaN, InGaN and AlGaN.
In FIG. 7A, with wires bonded to the second electrode layer 114 in
the frame part 111 and the semiconductor laser element 170, the
second electrode layer 114 is electrically connect to the
semiconductor laser element 170. For example, using a wire bonding
device, one end of an Au wire is bonded to the semiconductor laser
element 170, and the other end is bonded to the second electrode
layer 114. When a protective element such as a Zener diode is
arranged on the sub-mount 160, the protective element is also
electrically connected by the wire 180.
As shown in FIGS. 6A and 6B, the step portion for providing the
second electrode layer 114 is provided along three sides in top
view, and is not provided along one side except for portions
overlapping other sides.
The light reflecting member 150 is disposed between the one side
along which the step portion is not formed and the semiconductor
laser element 170 or the sub-mount 160, and the side along which
the step portion is not formed is located at a side opposite to the
semiconductor laser element 170 with the light reflecting member
150 disposed therebetween. Light radiated from the semiconductor
laser element 170 is reflected by the light reflecting member 150
to travel upward. As can be understood from FIGS. 7A and 7B, if the
side along which the step portion is not formed is provided with a
step portion, and the second electrode layer 114 on the side is
electrically connected to the semiconductor laser element 170 by
the wire, the wire is present in a light traveling direction, and
thus blocks the light. In view of this, a step portion for the
second electrode layer 114 is not provided on a side at the light
reflecting member 150 side, and thus the second electrode layer 114
can be appropriately disposed to allow reduction in the size of the
light emitting device 1.
In FIG. 8A, the frame part 111 of the base member 110 and the cover
120 are bonded together to hermetically seal a space in which the
semiconductor laser elements 170 is arranged. For example, on the
lower surface of the cover 120, a region bonded to the base member
110 is provided with a metal film, and the base member 110 is
bonded and fixed to the cover 120 via AuSn or the like disposed
therebetween. The semiconductor laser elements 170 are disposed in
the closed space, so that collection of organic substances and the
like on the light emitting end surface of the semiconductor laser
element 170 can be reduced.
For the cover 120, for example, glass provided with a metal film or
sapphire provided with a metal film can be used, and in particular,
it is preferable to use sapphire provided with a metal film. While
spread of light causes increase in size of a lens portion to
transmit the light, using sapphire for the lens portion of the lens
member 140 allows for reducing degree of spread of light because
sapphire has a relatively high refractive index, so that the size
of the lens portion of the lens member 140 can be reduced. Further,
sapphire has relatively high strength, and is therefore hardly
broken, so that hermetic reliability of a closed space can be
secured.
In FIG. 9A, the base member 110 is mounted on the substrate 100.
The substrate 100 is bonded to the bottom surface of the frame part
111 and the bottom part 118 of the base member 110. The bonding can
be performed by soldering. As shown in FIGS. 9B and 9C, the
substrate 100 includes a heat dissipation portion 101, an
insulating portion 102 and the metal film 103. The heat dissipation
portion 101 is formed of, for example, a metal such as Cu, the
insulating portion 102 is formed of an insulating material, and the
metal film 103 is formed of a metal such as Cu similarly to the
heat dissipation portion 101.
The heat dissipation portion 101 is bonded to the bottom part 118
of the base member 110, and the metal film 103 or the insulating
portion 102 is bonded to the frame part 111. Thus, the substrate
100 is designed such that the metal film 103 and the heat
dissipation portion 101 are provided on the same plane. More
specifically, the heat dissipation portion 101 has a protruded
structure protruded toward the base member 110 in a cross-sectional
view or a side view, and is formed so as to be exposed in a region
bonded to the bottom part 118 of the base member 110. On the other
hand, in a region where the substrate 100 is bonded to the frame
part 111, the heat dissipation portion 101 does not protrude, and
the heat dissipation portion 101 is not exposed by the insulating
portion 102 disposed on the heat dissipation portion 101. In a
bonding region of the substrate 100 that corresponds to a side of
the frame part 111 provided with the first electrode layer 112, the
metal film 103 is disposed on the insulating portion 102. Further,
a predetermined spacing is provided between the heat dissipation
portion 101 and the metal film 103 so that the heat dissipation
portion 101 and the metal film 103 are not in contact with each
other and electrically connected to each other. A part of the
region provided with a predetermined spacing overlaps a part of the
gap between the frame part 111 and the bottom part 118.
FIG. 9D is a top view of a bonding surface of the substrate 100
which is bonded to the base member 110. As shown in FIG. 9D, at the
bonding surface of the substrate 100, the substrate 100 includes
the insulating portion 102, the metal film 103, and an exposed
portion 106 (a protruding section having an exposed surface) in
which the heat dissipation portion 101 is disposed. Further, the
metal film 103 includes metal regions 104 and an insulating region
105. The exposed portion 106 is bonded to the bottom part 118, and
the metal regions 104 is bonded to the bottom surface of the frame
part 111.
The shape of the exposed portion 106 represents a region where the
heat dissipation portion 101 protrudes. In addition, the shape of
the exposed portion 106 corresponds to the shape of the bottom
surface of the bottom part 118, and is designed to have a size
slightly larger than a size of the bottom surface of the bottom
part 118. If the size of the exposed portion 106 is equal to the
size of the bottom surface of the bottom part 118, solder cannot
expand outward of the bonding surface when soldering, so that the
solder may have an excessive thickness between the substrate 100
and the base member 110. Further, in a top view, each metal region
104 includes two portions located at both sides of the insulating
region 105, Of the two portions of each metal region 104, a portion
located closer to the center of the substrate 100 is bonded to the
frame part 111. By the bonding, each of the metal region 104 is
electrically connected to a corresponding first electrode layer
112.
With the metal films 103 and the exposed portion 106 of the heat
dissipation portion 101 that are located at the same height, as
described above, it is possible to reduce lifting of the frame part
111 or the bottom part 118 from the substrate 100 when bonding of
the substrate 100 to the base member 110. If the degree of the
lifting is increased, bonding strength may be reduced, or a
non-bonded region may be partially formed, and therefore the
possibility that detachment of the package from a mounting
substrate occurs may be increased. Further, with the entirety of
bottom surface of the bottom part 118 bonded to the exposed portion
106 of the heat dissipation portion 101, heat can be efficiently
dissipated to the substrate 100.
In FIG. 10A, the lens member 140 is fixed to the cover 120 using an
adhesive agent. By the adhering, the adhesion portion 130 is formed
between the cover 120 and the lens member 140, and the light
emitting device 1 shown in FIGS. 1 to 3 is obtained. The adhesion
portion 130 is not formed on the entire region of the upper surface
of the cover 120 or the entire region of the lower surface of the
lens member 140, and is provided at such a position where the
adhesion portion 130 does not interrupt a path of light emitted
from the semiconductor laser element 170. More specifically, in the
light emitting device 1, a main part of light emitted by the
semiconductor laser element 170 is incident on and emitted from a
region of the lens member 140 which has a lens shape. Therefore, it
is desirable to use the adhesive agent such that the adhesion
portion 130 is not formed on the lower surface of the lens member
140 which corresponds to the region having a lens shape, and the
adhesion portion 130 is formed in an outer peripheral region of the
lens member 140. It is preferable that an ultraviolet ray-curable
resin is used for an adhesive agent that forms the adhesion portion
130. An ultraviolet ray-curable resin can be cured in a relatively
short time without heating the resin, so that the lens member 140
is easily fixed at a desired position.
As shown in FIGS. 10B and 10C, the lens member 140 has a lens shape
in which a plurality of lens portions is connected. Further, the
lens member 140 is designed such that one lens portion corresponds
to one semiconductor laser element, and such that lens portions
transmit main parts of light radiated from different semiconductor
laser elements. For the lens member 140, for example, glass such as
BK7 or B270 can be used.
The light emitting device 1 according to the first embodiment is
manufactured in the manner described above. The steps for
manufacturing the light emitting device 1 is not limited to the
steps described above with reference to FIGS. 4A to 10A.
Second Embodiment
FIG. 11 is a sectional view of a light emitting device 2 according
to a second embodiment. The schematic view of the appearance of the
light emitting device 2 is not different from that in FIG. 1, and
the internal structure of the light emitting device 2 in top view
is not different from that in FIG. 2. The light emitting device 2
according to the second embodiment is different from the light
emitting device 1 according to the first embodiment in the
structure of a bottom part of a base member. In particular, in the
second embodiment, the bonding surface of the bottom part, which is
bonded to a substrate, is different from that in the first
embodiment. Thus, with an insulating portion and an exposed portion
on the bonding surface of the substrate that have shapes adapted to
the bonding surface of the bottom part, structures, materials and
the like as described in the first embodiment can be employed for
other configurations.
As described in the step related to FIG. 5A for the light emitting
device 1 of the first embodiment, it is desirable to dispose the
bottom part 118 such that the distance between the frame part 111
and the bottom part 118 is entirely uniform at the time of bonding
the frame part 111 to the bottom part 118. However, misalignment
may occur in the process of bonding. If the degree of misalignment
is great, a part of the bottom part 118 is brought into contact
with the frame part 111. Further, if the spacing between the bottom
part 118 and the frame part 111 is narrower than a designed
spacing, and accordingly the distance between the first electrode
layer 112 and the bottom part 118 at this part is reduced, then
electrical connection may be established between the first
electrode layer 112 and the bottom part 118 at the time of bonding
the frame part 111 and the bottom part 118 to the substrate 100 by
soldering, which may lead to defectiveness of a light emitting
device.
Thus, in the light emitting device 2 according to the second
embodiment, a depressed portion 214 is formed on at least the outer
edge of a bonding surface 215 of a bottom part 213 bonded with a
substrate 200. With this structure, the spacing between a frame
part 211 and a bottom part 213 along a plane corresponding to the
bottom surface, which is the bonding surface 215 bonded with the
substrate 200, of a base member 210 is greater than the spacing
between the frame part 211 and the bottom part 213 along a plane
corresponding to a bonding surface 212 bonded with the frame part
211.
FIGS. 12A and 12B show an example of the bottom part 213 having the
depressed portion 214. In one example, a protruded shape of the
bottom part 213 forms a depression of the depressed portion 214. A
protruding region having a protruded shape forms the bonding
surface 215 bonded with the substrate 200, and the bonding surface
215 may have a shape obtained by scaling down a shape similar to
the shape of an outer frame portion of the bottom part 213 as shown
in FIG. 12A, or a circular shape as shown in FIG. 12B. FIG. 13 is a
schematic view showing a bonding surface of the substrate 200 when
the protruding region has a circular shape. As shown in FIG. 13, an
exposed portion 201 has a circular shape in corresponding to the
bonding surface 215 of the base member 210.
The depressed portion 214 has a spacing and height that
sufficiently allows for preventing occurrence of the
above-described defect in a step of soldering the base member to
the substrate 200. For example, the light emitting device 1 of the
first embodiment is designed such that a spacing of about 0.1 mm is
provided in the light emitting device 1, and the depression may be
designed so as to have a width of about 0.1 mm as long as a spacing
of at least about 0.1 mm may be provided. Thus, even if the frame
part 211 is in contact with a lateral surface of the bottom part
213 at the bonding surface 212 side bonded with the frame part 211,
it is possible to maintain a spacing of about 0.1 mm between the
frame part 211 and the bottom part 213 on the bonding surface
bonded with the substrate 200. Further, for example, the light
emitting device 1 of the first embodiment is designed such that the
distance between the lateral surface 119 of the bottom part 118 and
the first electrode layer 112 is 0.3 mm or more. When the width of
the depression is designed, the width of the depression may be
similarly selected with consideration of the design of the frame
part so that a distance of approximately 0.3 mm from the first
electrode layer 112 is maintained. The spacing of 0.3 mm is one
example in design of the light emitting device 1, and a
predetermined spacing to be provided may be appropriately selected
according to the shape and materials of the light emitting
device.
Therefore, the depressed portion 214 preferably has a width similar
to a width of a gap that would be secured when the bottom part 213
does not have the depressed portion 214 and misalignment of the
bottom part 213 with respect to the frame part 211 does not occur.
The depressed portion 214 may have a width equal to or greater than
a width of the gap, or may have such a shape that a part of the
depression portion has a width equal to or greater than a width of
the gap, as in the bottom part 213 in which the protruding region
has a circular shape as shown in FIG. 12. However, because an
increase in width of the depression leads to a decrease in bonding
area with the substrate 200, it is desirable that the depressed
portion 214 be prevented from having an excessively large width for
attaining sufficient bonding, and the width of the depressed
portion 214 is desirably 0.1 mm to 0.5 mm. For example, when a
bonding surface has a circular shape as shown in FIG. 12, the
depressed portion 214 may be designed such that the narrowest part
of the depression has a width similar to that of a gap to be
secured.
Further, the depressed portion 214 secures a height that allows a
solder extended out from the bonding surface 215 of the bottom part
213 bonded with the substrate 200 to extend upward along a lateral
surface meeting the bonding surface 215 bonded with the substrate
200, and to be retained in the depression. The height of the
depressed portion 214 desirable to be secured is varied according
to a material and an amount of solder to be used. For example, the
depressed portion 214 secures a height of about 0.2 mm in the light
emitting device 2.
When the bonding surface bonded with the substrate has a
rectangular or square shape with four modified corners, as in the
bottom part 118 described for the light emitting device 1 or the
bottom part 213 shown as one example in FIG. 12, the exposed
portion at the substrate side has a shape according to the shape of
the bonding surface, and accordingly, self-alignment occurs at the
time of bonding the bottom part to the substrate.
On the other hand, when the bonding surface 215 bonded with the
substrate 200 has a circular shape as in the bottom part 213 shown
in FIG. 12B as one example, the exposed portion 201 at the
substrate side having a circular shape according to the shape of
the bonding surface allows the bonding surface of the bottom part
213 to be located inward of the outer periphery of the exposed
portion 201. Further, with the bonding surface 215 and the exposed
portion 201 having such circular shapes, even in a state where the
bonding surface 215 and the exposed portion 201 are bonded with
each other via a solder, the substrate 200 and the bottom part 213
are movable along a rotating direction of the circular shape until
the solder is solidified. With the bonding surface 215 bonded with
the substrate 200 and having a circular shape, when misalignment
occurs in arrangement of the frame part 211 and the bottom part
213, the arrangement can be adjusted in a rotating direction, so
that misalignment of the frame part 211 with respect to the
substrate 200 can be corrected.
First Modified Example
A light emitting device 3 according to a first modified example has
a structure different from that in the light emitting device 2
shown in the second embodiment, so as to obtain a light emitting
device in which the spacing between a frame part and a bottom part
along a plane corresponding to a bonding surface bonded with a
substrate is greater than the spacing between the frame part and
the bottom part along a plane corresponding to a bonding surface
bonded with the frame part.
FIG. 14 is a cross-sectional view of the light emitting device 3
according to the first modified example. As shown in FIG. 14, in
the light emitting device 3, a depressed portion 312 is formed in a
frame part 311, so that the spacing between the frame part 311 and
a bottom part 313 along a plane corresponding to a bonding surface
bonded with a substrate 300 is greater than the spacing between the
frame part 311 and the bottom part 313 along a plane corresponding
to a bonding surface bonded with the frame part 311. In other
words, a size of the area within the intersection line between the
inner surface of the frame part 311 and the bonding surface is
smaller than a size of an area within an intersection line between
the inner surface of the frame part 311 and the bottom surface of
the frame part 311 in the plan view. The light emitting device 3
may be produced by a method including processing the shape of the
frame part 311 as described above, and in the light emitting device
3, the substrate 100 in the first embodiment can be employed as
such unlike the light emitting device 2.
Second Modified Example
FIG. 15 is a cross-sectional view of a light emitting device 4
according to a second modified example. In addition, FIG. 16 is a
schematic view of a bottom part according to the second modified
example. As shown in FIG. 15, the light emitting device 4 includes
a bottom part 412, in which a bonding surface bonded with a
substrate 400 has a size smaller than a size of a bonding surface
bonded with a frame part 411 at a bottom part 412, and a lateral
surface 413 is inclined. With inclination of the lateral surface
413 as described above, the spacing between the frame part 411 and
the bottom part 412 on the bonding surface bonded with the
substrate 400 can be greater than the spacing between the frame
part 411 and the bottom part 412 at the bonding surface bonded with
the frame part 411. Instead of inclination of the bottom part 412,
the frame part 411 may be provided with inclination as in the first
modified example.
Certain embodiments and modified examples of the light emitting
device according to the present invention has been described above,
but the light emitting device for implementing the technical idea
of the present invention is not limited to these embodiments and
modified examples described above. For example, while a light
emitting device in which three semiconductor laser elements are
arranged has been described, one or more semiconductor laser
elements may be arranged in the light emitting device. Also, the
light emitting device may not include the light reflecting member
150 so that light radiated from a semiconductor laser element
travels in a direction of the lens member 140.
In addition, the light emitting device having configurations
described in the present disclosure is not limited to the
structures of the light emitting devices 1 to 4. For example, the
present invention can be applied even to a light emitting device
having a constituent element which is not illustrated in
descriptions of any of the light emitting devices 1 to 4, and
having difference in a structure from a structure in the light
emitting device as described above cannot be a ground for failure
to apply the present invention.
On the other hand, the present invention can be applied without
necessity of sufficiently including all constituent elements of the
light emitting device described in the embodiments and modified
examples above. For example, when some constituent elements of the
light emitting device disclosed in the first embodiment are not
described in claims, the constituent elements which are not
described in claims may have any appropriate structure, and the
freedom of design thereof such as replacement, omission,
modification of the shape, change of materials, and the like by a
person skilled in the art is accepted, with which application of
the invention is claimed.
The light emitting device described in certain embodiments can be
used for projectors, on-vehicle headlights, illuminations,
backlights of display devices, and the like.
* * * * *